U.S. patent number 4,469,374 [Application Number 06/323,662] was granted by the patent office on 1984-09-04 for automotive seat.
This patent grant is currently assigned to Namba Press Works Co., Ltd.. Invention is credited to Jo. Kashihara, Etsusuke Oda.
United States Patent |
4,469,374 |
Kashihara , et al. |
September 4, 1984 |
Automotive seat
Abstract
An automotive or similar type vehicle seat comprising a seat
back having an adjustable central portion which may be selectively
adjustably positioned to minimize driver fatigue. The adjustable
area is actuatable upon rotation of an adjustment knob which
controls rotation of a shaft which is connected via suitable
linkages to a pivotal support mechanism for pivotably adjusting the
central portion of the seat back.
Inventors: |
Kashihara; Jo. (Nakaune
Okayama, JP), Oda; Etsusuke (Futago Kurashiki,
JP) |
Assignee: |
Namba Press Works Co., Ltd.
(Okayamaken, JP)
|
Family
ID: |
23260181 |
Appl.
No.: |
06/323,662 |
Filed: |
November 20, 1981 |
Current U.S.
Class: |
297/284.4;
297/362 |
Current CPC
Class: |
B60N
2/66 (20130101) |
Current International
Class: |
A47C
7/46 (20060101); B60N 2/66 (20060101); B60N
2/64 (20060101); A47C 007/46 (); A47C 003/00 () |
Field of
Search: |
;297/284,362 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
26668 |
|
Apr 1981 |
|
EP |
|
140021 |
|
Feb 1980 |
|
DE |
|
1235051 |
|
May 1960 |
|
FR |
|
27124 |
|
Mar 1977 |
|
JP |
|
943124 |
|
Nov 1963 |
|
GB |
|
2055711 |
|
Mar 1981 |
|
GB |
|
Primary Examiner: Lyddane; William E.
Assistant Examiner: Brown; Peter R.
Attorney, Agent or Firm: Harness, Dickey & Pierce
Claims
I claim:
1. In a vehicle seat of the type having a seat portion, a seat back
portion including a bolster frame, and a moveable lumbar support
pad in the seat back portion, an improved lumbar support assembly
comprising:
a support frame pivotable about a generally horizontal axis about
the lower portion of said support frame,
a threaded axle mounted for rotation to the bolster frame extending
along a generally horizontal axis,
at least one thread holder engaging said threaded axle,
at least one joint rod having a first and second end, said first
end pivotably fixed to said thread holder,
a second axle pivotably attached to said joint rod second end, said
second axle engaging at least one elongated slot formed by the
bolster frame,
at least one joint lever having a first and second end, said first
end pivotably attached to said second axle, said second end
pivotably attached to said support frame whereby rotation of said
threaded axle causes said thread holder to move along said threaded
axle thus causing
the position of said second axle within said slot to change thereby
causing said joint levers to effect changes in the position of said
support frame.
2. The vehicle seat according to claim 1 wherein a pair of said
thread holders are pivotably fixed to a pair of said joint
rods.
3. The vehicle seat according to claim 2 wherein a pair of said
joint levers are pivotably attached to both said second axle and
said support frame.
4. The vehicle seat according to claim 2 wherein said threaded axle
includes first and second threaded portions, said portions having
opposing thread direction such that upon rotation of said threaded
axle, said thread holders move either toward or away from one
another along said threaded axle.
5. The vehicle seat according to claim 1 wherein a pair of said
slots are formed by said bolster frame.
6. The vehicle seat according to claim 5 wherein said slots extend
in a substantially vertical direction.
Description
BACKGROUND OF THE INVENTION
This invention relates in general to vehicular seats which helps
the driver and/or passenger feel more comfort and less fatigue. In
particular, this invention relates to automotive seats with a
mobile seat back which is adjustable to the contours of the
driver's body, and which thereby reduces fatigue of the driver and
results in a more comfortable ride.
In general, automotive seats have been designed in such ways that
minimize the fatigue of the driver during driving, i.e., the seat
backs have been designed with optimum stress-strain relationship.
It has been reported that positioning a vehicle seat back in the
position shown in FIG. 4 such that the maximum stress range (the
stress of 60 g/cm.sup.2 range in the Figure) is located at the
second and third lumbar vertebra gives a driver minimum fatigue and
maximum comfort during driving. However, such seat back designs fit
the body contour of an average driver, and depending upon body
contours of individual drivers and the reclining angle of the
particular seat, deviation from the optimum stress distribution
takes place, thus increasing fatigue and discomfort of the driver.
In addition, even if the driver sits in the optimum seating
configuration, sitting in the same position for prolonged time
causes constant stress on the same parts of the body, which often
leads to fatigue and discomfort of the driver.
BRIEF SUMMARY OF THE INVENTION
It is a general objective of the invention to provide a new and
improved vehicular seat which overcomes or reduces the deficiencies
of conventional vehicular seats described above. By incorporating
an adjustable, mobile seat back in a vehicular seat, a driver can
freely select the seat back position and adjust the seat back to
his own body contours.
The overall construction and design of the vehicular seat of this
invention is shown in FIG. 1. The seat back in the invention is
made up of two parts, namely, one part supported by the main seat
back frame and being relatively fixed, and the other part being
mobile with its movement controlled by an adjustment knob. The
separation of the seat back is made at the upper region of the high
body stress distribution (FIG. 4). When the upper part of the
mobile seat back comes forward toward the back of the driver (FIG.
1), the maximum stress range of lumbar vertebra goes upward, and
when the upper part of the mobile seat back goes backward away from
the back of the driver, the maximum stress range goes downward.
Consequently, the deviation from the optimum stress ranges due to
the difference in body contours of drivers can be corrected by
adjusting the mobile seat back.
Another objective is to enable the driver to adjust or correct the
body stress distribution to specific seating positions. When
driving congested streets or when driving with the seat back angle
of a reclining seat adjusted so that it is nearly verticle or only
slightly displaced from that position, the body stress becomes
concentrated at upper part of vertebra, thus deviating from the
optimum stress distribution.
Another object is to provide appropriate hold effects on the driver
regardless of his size and contours of body. As shown in FIG. 2,
both sides of the seat bolster are made thicker in order to support
the stress parallel to the seat back. The contact stress between
the body and bolster is too great for large drivers, while the
contact stress cannot be achieved for small drivers, resulting in
insufficient hold effect. The mobile seat back of this invention
enables a large driver to achieve adequate hold effect by moving
backward the upper part of the mobile seat back and also enables a
small driver to achieve the adequate hold effect by moving forward
the upper part of the mobile seat back.
Another object is to provide a driver during long distance driving
with more comfort and less fatigue by enabling occasional adjusting
and readjusting of the mobile seat back, which avoids the constant
stress on the same part of the body.
Another object is to provide a driver suffering fatigue due to long
hours of driving with corrective meatures via means for adjusting
seating positions; for example, by moving the upper part of the
mobile seat between back and forward, the driver during long hours
of driving can adjust the body stress on his back, thus
contributing to reduction of fatigue.
The objects described above can be achieved with the seat in the
invention. The driver in this seat can choose seating position and
adjust the mobile seat back in order to reduce fatigue during
driving.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is an elevated perspective view of a seat with the mobile
seat back of the present invention;
FIG. 2 is a partially broken-away view of the seat of the present
invention;
FIG. 3 is a longitudinal cross-sectional view of the seat back
taken along the line of body contour of a driver; and
FIG. 4 is a schemmatic and graphic body stress distribution-fatigue
analysis.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
From the drawings, it will be seen that the automotive seat of the
invention has a seat back consisting of two primary parts, namely,
the upper part 1 and the lower mobile part 2. Bolsters 3 are fixed
to the upper stationary part 1. In order to move the mobile part of
the seat back, a knob or switch is installed, as shown in FIG.
1.
FIG. 4 shows the body stress distribution which results in minimum
fatigue. Body stress distribution is dependent upon the contours of
individual driver's body, and therefore, in order to achieve the
body stress ranges (the areas of 40 g/cm.sup.2 or more in FIG. 4)
should be separated from whole seat back and should be made to move
independently and continuously so that the driver can achieve the
optimum body stress distribution with symmetry in respect to the
back seat.
The seat back of the invention is constructed, as shown in FIGS. 2
and 3. Tubular frame 5 supports the whole seat back and bolster
frames 6a and 6b with elastomeric foam, such as polyurethane foam,
and constitutes the upper stationary seat back part. The lower,
mobile part of the seat back 3 is constructed in such a way that
the driver can achieve the optimum stress distribution by adjusting
the angle of the lower, mobile part of the seat back. Both ends of
the frames of the lower, mobile part of the seat back are connected
to bolster frames 6a and 6b through supporting arms 8 and the upper
section of the frame is connected by joint levers 9a and 9b. The
joint levers 9a and 9b, which are connected to the mobile axle 11
at their lower ends, are capable of rotating as the axis 11 moves
up and down in the long holes 10 which are formed in the bolster
frames 6a and 6b. When the axle 11 moves upward, the mobile seat
back frame 7 starts to rotate about the axle 8 by the forces of the
joint levers 9a and 9b, whereby the upper part of the mobile seat
back moves forward to the driver's back. On the other hand, when
the axle 11 moves downward, the mobile frame 7 starts to rotate
backward about the axle 8. In order to move the axle 11 up and
down, the adjusting axle 12 is introduced at the back of the mobile
seat back frame 7. The both ends of the adjusting axle 12 are
supported by the holes in the side wall of bolster frames 6a and
6b. The adjusting axle 12 has reverse threads at its opposite ends,
and thread holders 13a and 13b have threads with the same pitch as
the threads on the axle 12. Rods 14a and 14b connect the thread
holders 13a and 13b and the axle 11. An adjusting knob is attached
at the end of the adjusting axle 12. By rotating the adjusting knob
4, the thread holders 13a and 13b move horizontally and this
movement causes the up-down movement of the axle 11 through the
joint rods 14a and 14b. Thus, the driver can move the mobile seat
back by rotating the adjusting knob 14.
As shown in FIGS. 2 and 3, the mechanism for moving the mobile seat
back is effectively contained in narrow space in the seat; yet this
mechanism exhibits strong enough force to move the mobile seat back
by overcoming the stress caused by the driver's back. Other types
of mechanisms for adjusting the mobile seat back in the invention
such as gears, cams, crankshaft or electronic motors can also be
conceivable within the scope of the invention.
* * * * *